cache_dependency_path type should be string supporting multi-line globs, not string|string[]

[SeanIFitch]

The current README describes cache_dependency_path as:

---

cache_dependency_path

Optional (type: string|string[], default: pnpm-lock.yaml) File path to the pnpm lockfile, which contents hash will be used as a cache key.

---

In practice, the action only accepts a single string, which can include glob patterns separated by newlines. The type string|string[] is therefore misleading.

Suggested change:

• Update the README to indicate that cache_dependency_path is of type string
• Document that multi-line glob patterns are supported

Example usage:

cache_dependency_path: |
  ./frontend/pnpm-lock.yaml
  ./aws/pnpm-lock.yaml

This will correctly hash both files for caching.